Intercourse must take place frequently, particularly before and around the time of ovulation, and the couple must have been trying to conceive for at least one year (6 months if the woman is over 35 years old). Using these criteria, about 10-20% of all infertile couples have unexplained infertility. However, the percentage of couples classified as having unexplained infertility will depend upon the thoroughness of testing and the sophistication of medical technology. 
When transferring more than one embryo, the risk of pregnancy and newborn complications also increases.1 Among IVF babies, twins are 12 times more likely than singletons to be delivered prematurely, 16 times more likely to be underweight and 5 times more likely to suffer from respiratory complications. Among IVF mothers, mothers of twins are 2.5 times more likely to have pre-eclampsia, over 8 times more likely to have premature preterm rupture of membranes and 4 times more likely to require a Caesarean section.
Nonmedicated cycle with IUI: Also known as natural cycle IUI, a non-medicated cycle with IUI is often used by single women or same-sex female couples who are not directly experiencing infertility, but rather a lack of sperm. This treatment involves tracking the development of the egg that is naturally recruited during a menstrual cycle and then introducing the donated sperm. You will come into the office for two to four monitoring appointments to track egg development and cycle timing.
In a bid to understand my chances of IVF success, I took a quick dive through the vast information available from these sources and came away thinking I had the information I needed. I skipped merrily along thinking things looked pretty promising after reading my chances of IVF working the first time was somewhere around the 40% mark. I naively thought that meant I had an 80% chance if I did two cycles, and that I’d definitely have a baby after three rounds at the most. Unfortunately as later reflection revealed, math and statistic just don’t work like this…

Luteal support is the administration of medication, generally progesterone, progestins, hCG, or GnRH agonists, and often accompanied by estradiol, to increase the success rate of implantation and early embryogenesis, thereby complementing and/or supporting the function of the corpus luteum. A Cochrane review found that hCG or progesterone given during the luteal phase may be associated with higher rates of live birth or ongoing pregnancy, but that the evidence is not conclusive.[79] Co-treatment with GnRH agonists appears to improve outcomes,[79] by a live birth rate RD of +16% (95% confidence interval +10 to +22%).[80] On the other hand, growth hormone or aspirin as adjunctive medication in IVF have no evidence of overall benefit.[30]